Method and apparatus for forming an accurately dimensioned metal strip having varying thickness

ABSTRACT

A method and apparatus for forming an accurately dimensioned metal strip having a plurality of thicknesses in which a feed strip is passed through a pair of work rolls, one or both of which has a raised portion for forming the desired shape during the reduction, wherein both work rolls are supported by back-up rolls which rotate in engagement with the work rolls with one or both of the back-up rolls having a notched recess to accommodate raised portions of the work roll.

United States Patent Laigle et a1.

[ Sept. 10, 1974 METHOD AND APPARATUS FOR FORMING AN ACCURATELY DIMENSIONED METAL STRIP HAVING VARYING THICKNESS [75] Inventors: Roger E. Laigle, Torrington; Antone F. Rakich, Waterbury, both of Conn.; William J. Sivakoff, Buffalo, NY.

[73] Assignee: Anaconda American Brass Company, Waterbury, Conn.

[22] Filed: Aug. 30, 1972 [21] Appl. No.: 285,015

[52] U.S. Cl. 72/241, 72/366 [51] Int. Cl. B211) 29/00, 1321b 1/08 [58] Field of Search 72/241, 366, 224, 225,

[56] I References Cited UNlTED STATES PATENTS 1,900,032 3/1933 Worthington 72/247 X 1,915,084 6/1933 Bonsall 72/366 1,997,871 4/1935 Miller et a1 72/366 X 2,271,459 1/1942 McConnell 72/248 X 3,446,048 5/1969 Marcovitch... 72/88 3,488,989 l/1970 Rakich et a1.. 72/366 3,593,556 7/1971 Biain 72/241 3,765,213 10/1973 Townsend 72/249 Primary Examiner-Milton S. Mehr 1 ABSTRACT A method and apparatus for forming an accurately dimensioned metal strip having a plurality of thicknesses in which a feed strip is passed through a pair of work ro11s, one or both of which has a raised portion for forming the desired shape during the reduction, wherein both work rolls are supported by back-up rolls which rotate in engagement with the work rolls with one or both of the back-up rolls having a notched recess to accommodate raised portions of the work roll.

3 Claims, 7 Drawing Figures METHOD AND APPARATUS FOR FORMING AN ACCURATELY DIMENSIONED METAL STRIP HAVING VARYING THICKNESS BACKGROUND OF THE INVENTION Metal strips having non-rectangular cross-sections have been fullycontoured or shaped using machining operations to remove selected portions of the metal. These techniques require costly metal cutting operations resulting in substantial scrap losses. Rolling operations have also been employed to shape such metal strips; however, prior rolling techniques have failed to properly maintain the straightness of the strip and produce the required tolerances for certain applications.

Dual roll forming operations are disclosed in U.S. Pat. Nos. 3,488,988 and 3,488,989 assigned to the assignee of the present application but these dual rolling techniques are not suitable in certain circumstances to produce contour strips having dimensions within limited tolerance ranges.

SUMMARY OF THE INVENTION Broadly, the present invention is a method and apparatus for rolling a feed metal strip to a finished strip having substantial variations in thickness using a fourroll mill in which one or both strip-engaging work roll has a raised portion with each work roll being supported by a back-up roll complementarily notched as required to accomplish the simultaneous reduction and reforming of a plurality of portions of the feed strip.

It is a feature of the invention that a work-roll backup roll combination is used to allow the production of thinner cross'sections than heretofore attainable by the use of a pair of contoured work rolls alone. Those skilled in the art will recognize the lower limit of thickness rolled as a function of the work roll diameter. The use of a four-roll configuration provides a means of utilizing work rolls having smaller diameters, and thusly producing thinner material meeting close dimensional requirements.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic view of the apparatus used in practicing this invention;

FIG. 2 is a sectional view along line 22 of FIG. 1;

FIG. 3 is a sectional view along line 3-3 of FIG. 1;

FIGS. 4, 5 and 6 are sectional views of alternative strip configurations suitable for processing by the method of the present invention;

FIG. 7 is a sectional view illustrating an alternative embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, FIG. 1 includes payout reel 11 which pays out a feed strip 12. The feed strip may be formed by welding longitudinally together two or more strips to provide a composite feed strip having a cross sectional configuration more closely approximating the desired shape but other techniques of forming the feed strip may be used. Alternatively, the strip may be formed by rolling, skiving, routing, swaging or partial machining. FIG. 2 illustrates the sectional view of a welded composite feed strip having two sections, 13 and 14 joined by weld 15. A method of producing a longitudinally composite welded strip is disclosed in Lozano et al. U.S. application Ser. No. 169,203 filed Aug. 5, 1971, which application has been assigned to the assignee of the present application.

Other examples of feed strip configurations are shown in FIGS. 4-6. Since the amount of reduction and reforming of the strip is normally small, the finished or contoured shape has essentially the same appearance as the feed strip and is therefore not shown in the Figures.

Strip 12 is passed between strip-engaging or work rolls 16 and 17. Work roll 16 has raised portion 18 which is accommodated by notched recess portion 22 of back-up roll 23. Lower work roll 17 is shown having notched recess 21 but it may, if desired, have a uniform diameter provided its spacing from the upper work roll 16 is proper.

Back-up rolls 23 and 24 preferably have diameters substantially larger than work rolls 16 and 17 and through their size and position, serve to guide, steady and apply pressure to work rolls 16 and 17. While it is preferred that the back-up rolls are larger than the work rolls, this is not required for satisfactory operation. The shape and length of the work rolls and backup rolls may be varied to process strips of varying width and shape such as those illustrated in FIGS. 4-6.

Turning to FIG. 7, upper back-up roll 30 has a notched recess 31 to accommodate the raised portion 32 of upper work roll 33. Strip 12a is shown being reformed by upper work roll 33 and lower work roll 34 which roll has a raised portion 35. Lower back-up roll 36 has complementary recessed portion 37. It should be noted that raised portion 32 may in some applications not protrude beyond the surface of roll 33 and in such applications the back-up rolls would not need to be complementarily notched.

Referring to FIGS. 3 and 7, it will be seen that one or both of the work rolls may be notched, recessed or have raised portions and similarly the back-up rolls may be notched, recessed or have raised portions to accomplish reforming of strips of particular crosssectional configurations without interference between rolls while maintaining sufficient engagement of work and back-up rolls to provide the guiding, steadying and pressure application by the back-up rolls.

Accurate dimensioning can be obtained for all or some dimensions of the finished strip provided the raised portions 18, 32 and 35 of the work rolls and other work roll strip-engaging areas engage and control the movement of metal in the areas where such accurate dimensioning is desired. As an example of the practice of the present method, a feed strip, shaped as shown in FIG. 2, was processed using work rolls of about 1 V2 inch diameter. Two passes were used. The dimensions (see FIG. 2) as welded, after the first pass and after the second and final pass are set forth below:

3 4 Various driving arrangements for driving one or and accommodated raised portion spaced apart more of the rolls may be used. For example, one or one from the other; and both work rolls or one or both back-up rolls may be d. driving one or more of said rolls to cause the strip driven. The technique of driving both work rolls is preto move through the work rolls and be accurately ferred. 5 reduced and reformed.

We claim: 2. Apparatus for rolling a feed strip to form an accu- 1. A method of producing an accurately dimensioned rately dimensioned finished strip having varying thickmetal strip which varies in thickness comprising ness comprising a. introducing a feed strip having substantially the a. a pair of work rolls mounted for rotation about same overall cross sectional configuration as that to substantially parallel axes with one such roll having of the finished strip to be formed between two work rolls mounted for rotation about substantially i. a raised portion; and parallel axis, at least one of which rolls has spacedii. two end portions on either side of the raised porapart portions of selected diameter and has an intion; termediate raised portion with a diameter greater b. a notched back-up roll having a notched recess to than the selected diameter; accommodate the said raised portion which backb. supporting each work roll with a back-up roll up roll is positioned to engage the end portions of which back-up rolls are positioned to engage and the raised-portion roll to provide support for the apply pressure to the spaced-apart portions of the work roll and which notched recess is shaped to acwork rolls; commodate the raised portion without engagement c. employing back-up rolls to engage said work rolls with said portion; and

through the end portions of the back-up rolls, said c. a back-up roll supporting the work roll adjacent back-up rolls having a notched recess intermediate the notched work roll. of said end portions to accommodate the raised 3. The apparatus of claim 2 in which selected rolls portion protruding beyond the surface defined by are driven. the end portions of a work roll, said notched recess 

1. A method of producing an accurately dimensioned metal strip which varies in thickness comprising a. introducing a feed strip having substantially the same overall cross sectional configuration as that of the finished strip to be formed between two work rolls mounted for rotation about substantially parallel axis, at least one of which rolls has spaced-apart portions of Selected diameter and has an intermediate raised portion with a diameter greater than the selected diameter; b. supporting each work roll with a back-up roll which back-up rolls are positioned to engage and apply pressure to the spaced-apart portions of the work rolls; c. employing back-up rolls to engage said work rolls through the end portions of the back-up rolls, said back-up rolls having a notched recess intermediate of said end portions to accommodate the raised portion protruding beyond the surface defined by the end portions of a work roll, said notched recess and accommodated raised portion spaced apart one from the other; and d. driving one or more of said rolls to cause the strip to move through the work rolls and be accurately reduced and reformed.
 2. Apparatus for rolling a feed strip to form an accurately dimensioned finished strip having varying thickness comprising a. a pair of work rolls mounted for rotation about substantially parallel axes with one such roll having i. a raised portion; and ii. two end portions on either side of the raised portion; b. a notched back-up roll having a notched recess to accommodate the said raised portion which back-up roll is positioned to engage the end portions of the raised-portion roll to provide support for the work roll and which notched recess is shaped to accommodate the raised portion without engagement with said portion; and c. a back-up roll supporting the work roll adjacent the notched work roll.
 3. The apparatus of claim 2 in which selected rolls are driven. 